Abstract

Normal human bronchial epithelial cells (BE) and adenovirus-12 SV40 hybrid virus transformed, non-tumorigenic human bronchial epithelial cells (BEAS-2B) were cultured for 7 days in a serum free hormone supplemented medium. BE cells after 3 days in culture were exposed to conditioned medium (CMt) from confluent BEAS-2B cells. By day 7, CMt-treated BE cells exhibited a lower colony forming efficiency (CFE), fewer cells per colony, and a reduced mitotic index (MI) and BrdU (bromodeoxyuridine) labeling index. CMt also enhanced the expression of a terminally differentiated squamous phenotype in BE cells. Cell free lysates from BEAS-2B cells (CFLt) had effects similar to CMt on the MI and morphology of BE cells. In contrast, CMt and CFLt did not inhibit the growth, or alter the morphology of BEAS-2B cells. Conditioned medium from BE cells (CMn) did not reduce the growth of BEAS-2B cells, and had little effect on the morphology of BE cells. In co-cultures